Preparation of the higher monoacylamides from monoamides and acid halides



Patented Mar. 16, 1954 PREPARATION OF THE HIGHER MONOACYL- AMIDES FROM? MON OAMIDES. AND ACID HALIDE S Otto Turinsky; Western Springs, and Richard A. Rock, Chicago, Ill., assignorsto Armour and (lompany, ;.(lhicago,; 111., a corporation of Illinois No Drawing. Application February 24', 1948; Serial No. 10,584

5. Claims.

This invention relatesv to the. preparation of the; highermonoacylamides from monoamides and acid halides. Qne phase. of. the; invention is the: Production of a high molecular weight diamide of the general formula i i Rae-Nisan...

in which R and Rn may or maynot be the same and-in whichv the R or. both of the radicals contain at least-12 carbon atoms.

This application constitutes a continuationi n.-part of ourcopending application Serial No. 678,680 filed June;2,2,. 1946, nowabandoned.

Prior processes. suggested for the. forming of low molecular weight. diamides' have been unsatisfactory, either because. of. low" yields, difiiculty in preparing certain of the reagents, or because of, general commercial infeasibility. No satisfactory rocess .has been developed in which quantitative or. substantially quantitative yields are obtainedwhile using ordinaryandreadily available reagents Further, itv has not. heretofore. been possible to produce a. high molecularweight diamide, although in recent years. a claim hasbeen Inadefor the production of adistearamide. Examination of the process. andv the product. reveals. that. the author: was mistaken and that the product actually was a steamnitr ls- An obj ect of the. present invention is. toproduce.

a. new. composition; of, matter in..the: form. of a,

monoacylamide of high molecular weighthaving; new and valuable properties... Aiurther object. is. to provide a process :which. employs readily-avails.

able and. inexpensive, reagents. and bywhichwe substituted bygroups inert to; the. acid'ichloridev or: tmanyaother acid;halide.employedi The reaction is.

In the carrying out of our process, we prefer to maintain the reacting materials under reduced pressure or vacuum, the degree of the vacuum being such as. to remove the hydrogen chloride rapidly so that secondary reactions are prevented. Further, the reduced pressure or vacuum removes air which is undesirable as tending to cause a. darkening of the product. Yet another advantage of the vacuum is that the operation can be carried on at low temperature which further minimizes the danger of secondary reactions. We prefer to employ mechanical agitation during the reaction in order to further enhance the removal of the hydrogen chloride.

The. starting material. may be any'monoamide or any mixture of monoamides, such as, for example, a mixture of stearo, palmitic and oleic amides. The starting material may be a commercial mixture. of monoamides and may be a relatively impure mixture. Depending upon the mixture. of amides, temperature and other conditions may be varied to give the best results.

Any suitable temperatures may be used. Ordinarily, a temperature slightly above the normal melting point. of the amide may be used, such as; for example, C. The range of 100 C. to C. and above has ordinarily been satisfactory, but it will be understood thatconsiderable variation in temperaturemay' be desired by reason of the changing of other conditions, such asathe: degreeofi vacuum, nature of reactants, etc.

With. purified starting materials, yields of monoa'cylamides'are obtained which are practically quantitative; while theyields from thecommercial l. grades of starting materials are also very high, ranging but a few percent under the calculated amount. The high molecular mono-- acylamide obtained is. a waxy product which ismuch less soluble than the monoamide in polar solvents. Itisvaluable for use intextile treating materials and for'many other uses. The best high molecular product is obtained when thestarting amide material" has acarbon length between C12 and C22.

The degree of vacuum which is necessary in: the preferred process will vary not only for the particular startingmaterial' and other conditions but also it-willivary' during thereaction operation, a'gerater vacuum being required. at onetime than at anotherdue to the-great evolution of hydrogenchlor-ide. Generally, a vacuum of from 1 to 100- mm. of mercury is operable. p

Any: acid halide: may be employed, as has already been. indicated? .but' the." acid chloride is greatly preferred-because of'its unusual: effectiveness in the operation and because it results in a superior product.

Examples of the process may be set out as follows:

Example 1.--A mixture of 0.066 mole (18.7 grams) of recrystallized stearamide and 0.066 mole (19.9 grams) of vacuum distilled steroyl chloride was heated under vacuum mm.) in an oil bath. Appreciable bubbling (due to the evolution of I-lCl) did not take place until the temperature reached 100-105 C. The temperature was held at 105-110 C. for 1 /2 hours, the rate of HCl evolution diminishing rapidly at this stage. The heating was continued for another 3 hours with the temperature reaching a maximum value of 140 C. By this time the evolution of 1101 has ceased. Weighings showed that a theoretical amount of 1101 had been evolved and that the yield of crude distearamide (38.2 grams melting at 90-95" C.) was practically quantitative. The distea amide in contrast with stearamide was found to be quite insoluble in hot 95% ethanol but readily soluble in chloroform and carbon tetrachloride. On recrystallization from carbon tetrachloride there was obtained a yieldof 30.8 grams (85% of the total) melting point IDS-106 C. Analysis showed 2.60% nitrogen (the calculated value is 2.55%).

Example 2.Lauric-myristic amide was prepared from 0.1 mole of recrystallized lauric amide and 0.1 mole of re-distilled myristoyl chloride according to the procedure given under Example l. Again the yield obtained was nearly quantitative. The melting point of the recrystallized product was 93.0-93.5 C. Analysis showed 3.50% nitrogen (the calculated value is 3.42%).

Emtmple 3.Dilauramide was prepared from mole (99.6 grams) of lauric amide and mole (110 grams) of lauroyl chloride accord-- ing to the procedure given under Example 1, except for the fact that the pressure was maintained at 93-111 mm. pressure and the total heating time was reduced to 1%. hours. The reaction appeared to be quite complete since the evolution of HCl became negligible toward the end of this heating period. The recrystallized dilauramide had a melting point of 97-98 C. Analysis showed 3.62% nitrogen (the calculated value is 3.67%).

Example 4.Roughly A; mole (75.5 grams) of commercial stearoyl chloride was heated with an oil bath at 8595 C. under a vacuum (-65 mm. pressure) with agitation for about hour in order to remove volatile chlorine compounds. To this was then added '21 grams (roughly mole) of commercial stearamide and the vacuum heating with occasional agitation (-70 mm. pressure) was resumed. The reaction temperature was held at 100-115 C. for 1 hour being allowed to rise slowly to a maximum of 135 C. toward the end of 2 hours making the total heating time 3 hours. The crude distearamide thus obtained (melting point 85-88 C.) was practically of the same color as the original stearamide.

Ezzzample 5.A 100 pound quantity of commercial distearamide was prepared according to the procedure given in Example 4. The product was found to be a little superior (melting point 88-90" C.) to that described in Example 4.

Example 6.-One mol. of commercial stearic acid was treated with phosphorous trichloride and carbon tetrachloride in the usual manner.

The residue can be assumed to be -90 stearoyl chloride. To this was added .9 mol. of steamamide and the mixture heated at to 120 C. for three hours under water pump vacuum. The product was allowed to cool and was then washed with 200 cc. of warm 3A alcohol. The residue melted at 103 to 105 after filtration, and weighed 430 g., indicating a yield of 80%, starting from stearic acid. The yield is actually near quantitative when the yield of intermediate reactions and purity of compounds are considered.

The product is a crystalline wax-like material of very light color. 'The melting point of 103 to 105 compares favorably with the highly purified. sample which has a melting point of In a calre the material readily crumbles to a fine powder.

An inert gas was used instead of vacuum, but was found to be unsatisfactory because the product was dark in color and low in yield as a result of more side reactions. By using vacuum, we were able to maintain low temperatures, well below 140 (3., and as a result a much superior 1 product was obtained. With vacuum, the temperatures may be maintained for the most part in the range of 100-120 C. with excellent results, as indicated in the above examples. When using an inert gas, the temperatures were higher and more commonly in the neighborhood of 140 C. and above. As an example of the process using inert gas, the following may be set out:

A mixture of 75.6 g. rnole) of stearoyl chloride and 7.08 g. (M; mole) of stearamide was carefully heated in an oil bath. During the entire heating time the reaction mixture was agitated mechanically while a moderate stream of nitrogen bubbled through.

The total heating time was 2 hours during which the temperature was allowed to rise from C. to C. being at the latter value for the greater portion of the time. The yield of partly purified distearamide (melting point 95- 98 C.) was 39 grams or 28 72; of the theoretical yield.

The use of vacuum in the process, as indicated by the above examples sharply improves the yield, while at the same time resulting in a light-colored product. The use of vacuum instead of inert gas removes the HCl at such an increased rate that the main side reactions, namely, that of the formation of nitrile and fatty acid are practically eliminated. By quickly removing the hydrogen chloride as it is evolved, while also employing a relatively low range of temperatures, an unusually fine product is obtained and with a yield which approaches a quantitative yield.

The aliphatic monoamide treated by the process is preferably one having from 12 to 18 carbon atoms, as indicated by the examples set out. It will be understood, however, that the process is applicable to higher molecular weight monoamides.

While in the foregoing specification, we have set forth the details of various steps which may be employed in the carrying out of the process, it will be understood that such details may be varied widely by those skilled in the art without departing from the spirit of our invent-ion.

We claim:

1. In a process for the preparation of monoacylamides, the steps of heating an aliphatic monoamide having from 12 to 18 carbon atoms and a higher fatty acid halide at a temperature of about 100-140 C. while maintaining the reacting materials under reduced pressure, said pres sure being sufiiciently low to remove substantially all of the hydrogen halide as formed.

2. In a process for the preparation of monoacylamides, the steps of heating an aliphatic monoamide having from 12 to 18 carbon atoms and a higher fatty acid halide at a temperature of about 100-140" C. and agitating the reacting mixture under reduced pressure, said pressure being sufi'iciently low to remove substantially all of the hydrogen halide as formed.

3. In a process for the preparation of monoacylamides, the steps of heating an aliphatic monoamide having from 12 to 18 carbon atoms and a higher fatty acid chlorid at a temperature of about 100-140 C., agitating the materials, and maintaining the materials at a pressure of about 1-100 mm. to remove the evolved hydrogen chloride.

4. In a process for the preparation of monoacylamides, the steps of heating a mixture consisting of an aliphatic monoamide having from 12 to 18 carbon atoms and a higher fatty acid chloride, in equal molar quantities, at a temperature of about -140 C., and maintaining the reacting materials under reduced pressure of the order of 1-100 mm. to remove the evolved hydrogen chloride.

5. In a process for the preparation of monoacylamides, the steps of heating an aliphatic monoamide having from 12 to 18 carbon atoms and a higher fatty acid chloride at a temperature of about IOU- C. while maintaining the reacting materials under reduced pressure of the order of 1-100 mm. to remove the evolved hydrogen chloride.

OTTO TURINSKY. RICHARD A. RECK.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,090,595 Jacobson Aug. 17, 1937 2,388,132 Fischer et a1 Oct. 30, 1945 

1. IN A PROCESS FOR THE PREPARATION OF MONOACYLAMIDES, THE STEPS OF HEATING AN ALIPHATIC MONOAMIDE HAVING FROM 12 TO 18 CARBON ATOMS AND A HIGHER FATTY ACID HALIDE AT A TEMPERATURE OF ABOUT 100-140* C. WHILE MAINTAINING THE REACTING MATERIALS UNDER REDUCED PRESSURE, SAID PRESSURE BEING SUFFICIENTLY LOW TO REMOVE SUBSTANTIALLY ALL OF THE HYDROGEN HALIDE AS FORMED. 